No electrical at all

A couple weeks ago I went out to move my 1974 Dodge Dart and when I did there were sparks coming from near where the fuse box is. When i reached to turn the lights on it shocked my hand. I turned the car off, and later started her up and everything was fine. I only moved the car around the house and turned it off. Now when i get in the car it acts like there is no battery in the car ar all. i have changed the battery out for 2 other know good ones and still I get no lights to come on at all including the dome light, and the motor won't even attempt to turn over. Everything is just dead.

I jumped the starter relay and the motor will turn over, so I put in a new park netural saftey switch and the car is still dead.

I have been doing research on this and found numerous refrences to the fusible link. I found the wire on the drivers fender that has a plastic tab that says fusible link on it, but don't know how to proceed from there. I have found some websites telling how to possibly fix this but it is all greek to me. Can anyone explain to me how to troubleshoot this and possibly fix it? Pictures would be a big help since this is my first attempt at something like this. I also have looked at the bulk head connector and wiggled the connections around, but it all appears to look ok. I would really like to fix this problem myself cause i don't have much money and and what little I do have I had planned to put on a new exhaust system and a couple other things. Thanks.